Mechanical systems within vehicles and equipment require adequate lubrication for many different reasons. Lubricants ensure that components move freely reducing both heat and friction and mitigating wear and tear. They also seal parts from harmful contaminants and corrosion and can keep parts cleaner, working at optimum and extending their active service life.
Lubricants take a wide range of forms, but perhaps the two most commonly deployed are oils and greases. While both these products are designed to achieve similar results and deliver the attributes listed above, there are some key differences, which make them suited to different roles. In this blog, we’ll compare these two solutions side-by-side and get to the heart of what sets them apart. Read on to find out more.
The simple differences between oil and grease
Grease and oil are familiar terms to most people. However, unless they operate in the field of lubrication, most are unclear on how they differ. For some processes and problems oil will be a better solution, although there are other applications where grease is more suitable. Thankfully, their key differences are not too complicated.
Oils are made from natural or paraffin-based oil and then specific additives are included in formulation to either supress or enhance innate properties of its base oil or add entirely new ones to help it perform its role. While oils are available in various levels of viscosity to flow freely, they are sold in liquid form.
Grease is typically made with an oil, and in a similar way it will usually include a collection of additives. However, one of these additives is always a thickening agent. This inclusion is added to it during production making it more viscous. A wide range of different agents are used. Sometimes a type of soap is used, or kind of clay known as bentonite. Another agent is the mineral molybdenum. However, most of the greases you’ll encounter will make use of a complex kind of soap, with the most common being lithium.
As a result, at room temperature, an oil will remain liquid, while a grease will be solid. All kinds of oil can effectively be turned into a grease, however, not every type of grease is derived from oils.
Aside from their viscosity, another key difference between oils and greases is the type of application for which they are used. As a rule, grease is typically used only on machinery, equipment and tools while oils are deployed for a multitude of other, often non-industrial uses.
When is grease a superior option than oil?
There are several situations where using grease can be the better choice for lubrication. The waterproofing ability of greases can be especially effective under circumstances where drippage or leakage exist. It is also exceptionally suited to areas of a system that are difficult to reach and when lubrication circulation just isn’t practical.
When an operating environment has elevated levels of contamination, either from dirt and debris, varnish or water particles, grease is great for sealing. As it stays in place due to its high viscosity, it is also ideal for protecting metal equipment from corrosion and rust, especially when it is not always in active service. Whether machinery is used intermittently or must be stored away for the season, grease provides excellent protection from the elements.
In high-load or slow-speed loading conditions, its viscosity also helps it suspend solid additives and, in manufacturing, it is added to sealed-in-for-life systems like electric motors. Other applications for greases include lubricating well-worn machinery, reducing noise and supplying effective lubrication under special and extreme operating conditions.
When should you choose oil over greases for lubrication?
Unlike greases, oils also have cooling properties. Oils can transfer heat away from parts into a bigger body of oil. This oil can then be pumped back through via a heat exchanger. When an application involves considerable heat generation, oil will not only provide lubrication but act as a coolant making it the best option to use.
Oils can also be deployed when greases are too difficult or impractical to use. While grease will remain in place, some mechanical systems require lubricants to feed through and reach different components keeping parts moving freely but also cleaning out dirt and debris. These particles are collected in the oils as it circulates and filtered harmlessly away into the sump where they cannot impair operations or damage components over time.
Finding the right lubricant for the job
Selecting the correct lubricant for each individual application is essential for users seeking optimum performance, equipment protection and extended years of use from mechanical systems. If you are unsure of whether an oil or grease is the best option for your needs, always consult a leading lubrication supplier or your original equipment manufacturer (OEM) recommendation